Preliminary evidence for performance enhancement following parietal lobe stimulation in Developmental Dyscalculia

Nearly 7% of the population exhibit difficulties in dealing with numbers and performing arithmetic, a condition named Developmental Dyscalculia (DD), which significantly affects the educational and professional outcomes of these individuals, as it often persists into adulthood. Research has mainly focused on behavioral rehabilitation, while little is known about performance changes and neuroplasticity induced by the concurrent application of brain-behavioral approaches. It has been shown that numerical proficiency can be enhanced by applying a small—yet constant—current through the brain, a non-invasive technique named transcranial electrical stimulation (tES). Here we combined a numerical learning paradigm with transcranial direct current stimulation (tDCS) in two adults with DD to assess the potential benefits of this methodology to remediate their numerical difficulties. Subjects learned to associate artificial symbols to numerical quantities within the context of a trial and error paradigm, while tDCS was applied to the posterior parietal cortex (PPC). The first subject (DD1) received anodal stimulation to the right PPC and cathodal stimulation to the left PPC, which has been associated with numerical performance's improvements in healthy subjects. The second subject (DD2) received anodal stimulation to the left PPC and cathodal stimulation to the right PPC, which has been shown to impair numerical performance in healthy subjects. We examined two indices of numerical proficiency: (i) automaticity of number processing; and (ii) mapping of numbers onto space. Our results are opposite to previous findings with non-dyscalculic subjects. Only anodal stimulation to the left PPC improved both indices of numerical proficiency. These initial results represent an important step to inform the rehabilitation of developmental learning disabilities, and have relevant applications for basic and applied research in cognitive neuroscience, rehabilitation, and education.

[1]  Brian Butterworth,et al.  Core information processing deficits in developmental dyscalculia and low numeracy. , 2008, Developmental science.

[2]  J. Delgado-García,et al.  Transcranial direct-current stimulation modulates synaptic mechanisms involved in associative learning in behaving rabbits , 2012, Proceedings of the National Academy of Sciences.

[3]  Roi Cohen Kadosh,et al.  The effect of transcranial direct current stimulation: a role for cortical excitation/inhibition balance? , 2013, Front. Hum. Neurosci..

[4]  Brian Butterworth,et al.  Rapid Communication: Understanding the Real Value of Fractions and Decimals , 2011, Quarterly journal of experimental psychology.

[5]  B. Day,et al.  Interhemispheric inhibition of the human motor cortex. , 1992, The Journal of physiology.

[6]  Andrea Facoetti,et al.  Developmental trajectory of number acuity reveals a severe impairment in developmental dyscalculia , 2010, Cognition.

[7]  Avishai Henik,et al.  The development of internal representations of magnitude and their association with Arabic numerals. , 2002, Journal of experimental child psychology.

[8]  R. Shalev.  Prevalence of developmental dyscalculia. , 2007 .

[9]  R. Cohen Kadosh,et al.  Numerical representation in the parietal lobes: abstract or not abstract? , 2009, The Behavioral and brain sciences.

[10]  Brian Butterworth,et al.  Information processing deficits in dyscalculia. , 2007 .

[11]  Avishai Henik,et al.  The Brain Locus of Interaction between Number and Size: A Combined Functional Magnetic Resonance Imaging and Event-related Potential Study , 2007, Journal of Cognitive Neuroscience.

[12]  Anja Ischebeck,et al.  On the relative speed account of number-size interference in comparative judgments of numerals. , 2003, Journal of experimental psychology. Human perception and performance.

[13]  Allen and Rosenbloom Paul S. Newell,et al.  Mechanisms of Skill Acquisition and the Law of Practice , 1993 .

[14]  L Girelli,et al.  The development of automaticity in accessing number magnitude. , 2000, Journal of experimental child psychology.

[15]  F. Hummel,et al.  Brain Stimulation and its Role in Neurological Diseases , 2014 .

[16]  R. Cohen Kadosh,et al.  The Mental Cost of Cognitive Enhancement , 2013, The Journal of Neuroscience.

[17]  Edwin M. Robertson,et al.  The Resting Human Brain and Motor Learning , 2009, Current Biology.

[18]  G. Schlaug,et al.  Bihemispheric brain stimulation facilitates motor recovery in chronic stroke patients , 2010, Neurology.

[19]  M Smith,et al.  Near infrared spectroscopy. , 1999, British journal of anaesthesia.

[20]  David A. Boas,et al.  Near-infrared spectroscopy shows right parietal specialization for number in pre-verbal infants , 2010, NeuroImage.

[21]  Roberto Cubelli,et al.  Selective spatial attention and length representation in normal subjects and in patients with unilateral spatial neglect , 1989, Brain and Cognition.

[22]  M. Koslowsky,et al.  tDCS polarity effects in motor and cognitive domains: a meta-analytical review , 2011, Experimental Brain Research.

[23]  Daniel Ansari,et al.  Neural correlates of symbolic number processing in children and adults , 2005, Neuroreport.

[24]  V Menon,et al.  Cerebral Cortex doi:10.1093/cercor/bhi055 Developmental Changes in Mental Arithmetic: Evidence for Increased Functional Specialization in the Left Inferior Parietal Cortex , 2005 .

[25]  Daniel B. Berch,et al.  Why is math so hard for some children? : the nature and origins of mathematical learning difficulties and disabilities , 2007 .

[26]  Gottfried Schlaug,et al.  Contralateral and ipsilateral motor effects after transcranial direct current stimulation , 2006, Neuroreport.

[27]  Hideo Tsukada,et al.  Neuronal Circuit Remodeling in the Contralateral Cortical Hemisphere during Functional Recovery from Cerebral Infarction , 2009, The Journal of Neuroscience.

[28]  Justin Halberda,et al.  Individual differences in non-verbal number acuity correlate with maths achievement , 2008, Nature.

[29]  Brian Butterworth,et al.  Basic numerical capacities and prevalence of developmental dyscalculia: the Havana Survey. , 2012, Developmental psychology.

[30]  Guilherme Wood,et al.  Developmental dyscalculia: compensatory mechanisms in left intraparietal regions in response to nonsymbolic magnitudes , 2009, Behavioral and Brain Functions.

[31]  Ann Dowker,et al.  Interventions for improving numerical abilities: Present and future , 2013, Trends in Neuroscience and Education.

[32]  Elizabeth K. Warrington,et al.  Arithmetic Skills in Patients with Unilateral Cerebral Lesions , 1986, Cortex.

[33]  Michael von Aster,et al.  Mental number line training in children with developmental dyscalculia , 2011, NeuroImage.

[34]  Tobias U. Hauser,et al.  Enhancing performance in numerical magnitude processing and mental arithmetic using transcranial Direct Current Stimulation (tDCS) , 2013, Front. Hum. Neurosci..

[35]  Justin Halberda,et al.  Number sense across the lifespan as revealed by a massive Internet-based sample , 2012, Proceedings of the National Academy of Sciences.

[36]  I M Williams,et al.  Near infrared spectroscopy , 1994, Anaesthesia.

[37]  L. Cohen,et al.  Influence of interhemispheric interactions on motor function in chronic stroke , 2004, Annals of neurology.

[38]  Avishai Henik,et al.  Are Arabic and verbal numbers processed in different ways? , 2008, Journal of experimental psychology. Learning, memory, and cognition.

[39]  A. Henik,et al.  Double Dissociation of Functions in Developmental Dyslexia and Dyscalculia , 2006 .

[40]  J. Bynner,et al.  Does Numeracy Matter? Evidence from the National Child Development Study on the Impact of Poor Numeracy on Adult Life. , 1997 .

[41]  M. Bikson,et al.  Computational Modeling Assisted Design of Optimized and Individualized Transcranial Direct Current Stimulation Protocols , 2014 .

[42]  George A. Alvarez,et al.  The Role of the Parietal Lobe in Visual Extinction Studied with Transcranial Magnetic Stimulation , 2009, Journal of Cognitive Neuroscience.

[43]  Michael von Aster,et al.  Optimized voxel-based morphometry in children with developmental dyscalculia , 2008, NeuroImage.

[44]  J. Gibson,et al.  A developmental study of the discrimination of letter-like forms. , 1962, Journal of comparative and physiological psychology.

[45]  Robert Plomin,et al.  Why is math so hard for some children? The nature and origins of mathematical learning difficulties and disabilities , 2007 .

[46]  J. Tzelgov,et al.  Automatic comparisons of artificial digits never compared: learning linear ordering relations. , 2000, Journal of experimental psychology. Learning, memory, and cognition.

[47]  Á. Pascual-Leone,et al.  Noninvasive human brain stimulation. , 2007, Annual review of biomedical engineering.

[48]  A. Dowker.  What Works for Children with Mathematical Difficulties ? The effectiveness of intervention schemes , 2009 .

[49]  Monica Hoyos Flight.  Axon guidance: A developmental switch , 2010, Nature Reviews Neuroscience.

[50]  Orly Manor,et al.  Developmental dyscalculia: a prospective six‐year follow‐up , 2005, Developmental medicine and child neurology.

[51]  W. Paulus.  Transcranial electrical stimulation (tES – tDCS; tRNS, tACS) methods , 2011, Neuropsychological rehabilitation.

[52]  Avishai Henik,et al.  Virtual Dyscalculia Induced by Parietal-Lobe TMS Impairs Automatic Magnitude Processing , 2007, Current Biology.

[53]  R. Shalev,et al.  Developmental Dyscalculia , 2004, Journal of child neurology.

[54]  Julie L. Booth,et al.  Numerical magnitude representations influence arithmetic learning. , 2008, Child development.

[55]  Gavin R. Price,et al.  Impaired parietal magnitude processing in developmental dyscalculia , 2007, Current Biology.

[56]  S. Varma,et al.  Dyscalculia: From Brain to Education , 2011, Science.

[57]  S. Dehaene,et al.  THREE PARIETAL CIRCUITS FOR NUMBER PROCESSING , 2003, Cognitive neuropsychology.

[58]  N. Thakor,et al.  Determination of current density distributions generated by electrical stimulation of the human cerebral cortex. , 1993, Electroencephalography and clinical neurophysiology.

[59]  D. Ansari.  Effects of development and enculturation on number representation in the brain , 2008, Nature Reviews Neuroscience.

[60]  Avishai Henik,et al.  Automatic and intentional processing of numerical information , 1992 .

[61]  R. Cohen Kadosh,et al.  Long-Term Enhancement of Brain Function and Cognition Using Cognitive Training and Brain Stimulation , 2013, Current Biology.

[62]  Avishai Henik,et al.  Meta-Analyses of Developmental fMRI Studies Investigating Typical and Atypical Trajectories of Number Processing and Calculation , 2011, Developmental neuropsychology.

[63]  J. Duncan.  An adaptive coding model of neural function in prefrontal cortex , 2001 .

[64]  R. C. Kadosh.  Using transcranial electrical stimulation to enhance cognitive functions in the typical and atypical brain , 2013 .

[65]  E. J. Carter,et al.  Functional Imaging of Numerical Processing in Adults and 4-y-Old Children , 2006, PLoS biology.

[66]  V. Walsh,et al.  Modulating Neuronal Activity Produces Specific and Long-Lasting Changes in Numerical Competence , 2010, Current Biology.

[67]  Families..  Department for Children, Schools and Families , 2007 .

[68]  D G Gadian,et al.  Calculation difficulties in children of very low birthweight: a neural correlate. , 2001, Brain : a journal of neurology.

[69]  Daniel Ansari,et al.  Age-related Changes in the Activation of the Intraparietal Sulcus during Nonsymbolic Magnitude Processing: An Event-related Functional Magnetic Resonance Imaging Study , 2006, Journal of Cognitive Neuroscience.

[70]  Melissa E. Libertus,et al.  Comment on "Log or Linear? Distinct Intuitions of the Number Scale in Western and Amazonian Indigene Cultures" , 2009, Science.

[71]  John Bynner,et al.  Does Numeracy Matter More , 2006 .